An empty storage tank has a volume of 4,850 ft3. What is the buoyant force exerted on it by the air? (Assume the air is at 0°C and 1 atm.)

Question

An empty storage tank has a volume of 4,850 ft³. What is the buoyant force exerted on it by the air? (Assume the air is at 0°C and 1 atm.)

Answer 1

The buoyant force is a product of the density of the medium displaced, the volume of the medium displaced, and gravity. In this situation, the air is the displaced medium. The magnitude for density, volume, and gravity are 1.275 kg/m³, 4850 ft³, and 9.81 m/s² respectively.

First, we can convert the volume from ft³ to m³ with the relationship, 1 meter = 3.281 ft.

V = 4850 ft³ / (3.281 ft)³ ·1 m³ = 137 m³. (Be sure to cube the conversion.)

Then, we can calculate the buoyant force, F_B = ρ·V·g. = 1.275 kg/m³ · 137 m³ · 9.81 m/s²

The buoyant force will be approximately equal to 1710 N.